ON SALT OF BENZOIN 139 



then take it from the fire and let it settle ; add the 

 supernatant liquor to the former ; pour upon the residuum 

 some more lime-water, boil it as aforesaid, and repeat the 

 same process once more. At last, put all the residuum 

 upon a filter, and pour hot water several times upon it 

 During this process the calcareous earth combines with the 

 acid of benzoin, and separates it from the resinous particles 

 of this substance. A small quantity of the resin is dissolved 

 by the lime-water, whence it acquires a yellow colour. All 

 these yellow leys and decoctions are to be mixed together 

 and boiled down to 2 lb., which are then to be re-strained 

 into another glass vessel. 



These lixivia are inspissated thus much, because super- 

 fluous water would hold much salt in solution, which must 

 afterwards be precipitated. Besides, a small quantity of the 

 resin, suspended by the lime-water, likewise separates during 

 the evaporation, not being soluble in a small quantity of 

 water ; it therefore remains in the strainer. After the 2 lb. 

 of the evaporated leys are grown cold, muriatic acid is to 

 be added, with constant stirring, till there be no further 

 precipitation, or till the mass tastes a little sourish. As 

 vegetable acids have in general a weaker attraction for 

 absorbent earths than mineral acids, the muriatic acid com- 

 bines with the calcareous earth, and the acid of benzoin, 

 which requires a large quantity of water to its solution, 

 must fall down ; the solution, which had before but a very 

 weak smell of flowers of benzoin, acquires by this precipita- 

 tion a very strong one. 



The precipitated coagulum is then to be put into a filter, 

 and, after being well dried, it is to be edulcorated sufficiently, 

 by repeatedly pouring cold water upon it ; it should be dried 

 afterwards in a gentle heat. But as the water made use 

 of for the edulcoration contains a little of the salt of 



